Diabetes is a disease process resulting from multiple causative factors and is characterized by elevated levels of plasma glucose during the fasting state or after administration of glucose during an oral glucose tolerance test. Persistent or uncontrolled hyperglycemia is associated with increased and premature morbidity and mortality. Abnormal glucose homeostasis is often associated both directly and indirectly with alterations of the lipid, lipoprotein and apolipoprotein metabolism and other metabolic and hemodynamic diseases. There are two generally recognized forms of diabetes. Type 1 diabetes (also known as insulin-dependent diabetes mellitus or juvenile-onset diabetes) develops when the body's immune system destroys the pancreatic cells that produce the hormone insulin, which regulates blood glucose levels. Type 1 diabetes accounts for about 5 to 10 percent of all diagnosed cases of diabetes. Risk factors for type 1 diabetes include autoimmune, genetic, and environmental factors. Type 2 diabetes (also known as non-insulin-dependent diabetes mellitus or adult-onset diabetes), is a metabolic disorder resulting from the body's inability to either sufficiently produce insulin or properly use it. The onset of type 2 diabetes is usually characterized by insulin resistance, a disorder in which cells do not respond to insulin properly. As a result, an increasing amount of insulin is needed, and the pancreas gradually loses its ability to produce insulin. Type 2 diabetes is the most common form of the disease, accounting for 90-95 percent of diabetes. Type 2 diabetes is becoming an epidemic due to a greater prevalence of obesity and sedentary lifestyle. Gestational diabetes refers to a form of glucose intolerance that is diagnosed in pregnant women. During pregnancy, gestational diabetes requires treatment to normalize maternal blood glucose levels to avoid complications in the infant. A small percentage (about 5-10 percent) of women with gestational diabetes develop type 2 diabetes after pregnancy. Women who have had gestational diabetes also have a 20-50 percent chance of developing diabetes in the next 5-10 years.
Along with diet and exercise, treatment with insulin or hypoglycemia drugs is commonly employed to control diabetes. Treatment with these agents is successful in some cases, but the mortality index continues to rise. Insulin treatment provides symptomatic relief rather than a cure for non-insulin-dependent diabetes mellitus (NIDDM). Hypoglycemic agents such as sulfonylureas and biguanides (metformin) also lower blood glucose, but again only provide symptomatic relief. Sulfonylureas lower the blood glucose level by stimulating the release of insulin from pancreatic beta cells. These agents directly stimulate insulin release by closing adenosyl triphosphate (ATP)-sensitive potassium channels and depolarizing the cell membrane. The side effects of sulfonylureas include hypoglycemia, renal and hepatic disease, gastrointestinal disturbances, increased cardiovascular mortality, dermatological reactions, dizziness, drowsiness and headaches. Biguanides lower blood glucose levels by reducing intestinal glucose absorption and hepatic glucose; however, they do not stimulate insulin secretion. The major side effects of biguanidine are lactic acidosis and increased cardiovascular mortality. Alpha glucosidase inhibitors inhibit intestinal alpha glucosidases and consequently delay the digestion of sucrose and complex carbohydrates. The side effects of alpha glucosidase inhibitors include gastrointestinal side effects and hypoglycemia. Thiazolidinediones improve insulin resistance directly, enhancing the effects of circulating insulin by directly stimulating peripheral glucose uptake and inhibiting glucose production in the liver. However, thiazolidinediones are only effective in the presence of insulin and may cause red blood cell abnormalities and headache. Therefore, researchers have long been interested in medicinal plants as a possible source for the development of anti-diabetic agents.
U.S. Pat. No. 6,780,440 provides herbal compositions suitable for weight loss management and for treating diabetes and comprising Ferula hermonis, an extract thereof or a combination of Ferula hermonis and selected herbs, extracts thereof, and a mixture thereof suitable for weight loss management. U.S. Pat. No. 6,770,307 refers to an herbal medicinal composition for preventing or treating type II diabetes, which comprises extracts from Pterocarpus marsupium, Morus alba, Orthosiphon aristatus, Opiophogon japonicus, Rosa rugosa, Commelina communis, Trichosanthis kirilowii and Anemarrhena asphodeloides. U.S. Pat. No. 6,576,270 refers to the herbal composition against diabetes, which consists of Centaurii umbellatum, Gentianaceae (centaury plant), Teraxacum officinale, Asteraceae (dandelion root), Juniperi communis L, Cupresaceae (juniper berry), Urticae dioica L, Urticeae (nettle plant), Urticae dioica L, Urticaceae (nettle root), Cichorium intybus L, Cichoriaceae (chicory root), Morus nigra L, Moraceae, (mulberry leaf), Achilleae millefolium L, Asteraceae (yarrow flower), Vaccinium myrtillus L, Ericaceae (bilberry leaf), Phaseolus vulgaris L, Fabaceae (bean pods), Valeriana officinalis L, Valerlanaceae (Valerian root). U.S. Pat. No. 7,482,030 refers to a new composition comprising the herbs Mulinum spinosum and Chamaemelum nobile for treatment of diabetes.
Even though Dhawan B. N. et al. (Indian Journal of Expertmental Biology, Vol. 15, March 1977, pp. 208-219) discloses that an essential oil extracted from the rhizome of Hedychium spicatum Buch-Ham, an allied species of Hedychium coronarium, has been found to be hypoglycaemic, and Bhandary M. J. et al. (Journal of Ethnopharmacology, 47 (1995) 149-158) found that a mixture of the dried rhizome powder of Hedychium coronarium Koening with milk is traditionally used at some area in India to treat diabetes, as concluded by Bhandary M. J. et al. (1995), in order to discover the true potential of these medicines, pharmco-chemical studies are needed. Therefore, there is a continued need for novel herbal medicaments for blood glucose reduction and treatment and/or prevention of diabetes.